This invention relates to power distribution systems, particularly power distribution systems for motor vehicles. More specifically, the invention relates to bus bars used in power distribution systems and most specifically, the invention relates to a modular bus bar system which employs molded, metalized components.
The electrical power distribution system is an important component of a wide variety of apparatus including motor vehicles, electrical appliances, industrial equipment and the like. Power distribution systems of any complexity typically include one or more bus bars which serve to carry relatively high levels of current to electrical devices such as fuses, relays and the like, from whence the electrical power is then conveyed to other components of the apparatus. The electrical systems of motor vehicles are of increasing complexity, and motor vehicles presently manufactured include an electrical distribution box having a number of bus bar assemblies therein. Presently, bus bars are fabricated from metal stampings. These bus bars are of relatively complex geometry and include a power connection terminal which is configured to engage a source of electrical power such as a battery or alternator, through a bolt or other such connection. Power bus bars further include a current carrying member having a number of connector prongs projecting there from, typically at right angles through the remainder of the assembly.
The complex geometrical shape of such bus bars precludes stacking. This, together with the general fragility of the metal stampings complicates shipping and handling. Furthermore, such prior art bus bars must be uniquely configured for each application. Therefore, in the motor vehicle industry, manufacturers are often required to employ differently configured bus bar assemblies for various models of vehicle; and in fact, a particular vehicle may require use of a number of discreetly configured bus bars. As a result, tooling and inventory problems associated with the use of prior art stamped metal bus bars are significant. In addition, prior art stamped metal bus bars are relatively heavy, and their manufacture typically generates a large amount of scrap metal which may not be easily recycled.
The present invention provides a bus bar system which allows for the assembly of bus bars of different electrical configurations from a number of standard, identical parts. The components of the system of the present invention are lightweight, rugged, and of generally planar geometry. As a result of the foregoing, problems of shipping, handling and inventory maintenance are greatly alleviated. The system of the present invention allows bus bar assemblies to be easily configured for specific applications from a relatively small number of standard components. In addition, the system of the present invention minimizes the amount of scrap generated in bus bar fabrication, and permits the ready recycling or reuse of system components. The system of the present invention has particular utility in connection with the power distribution system of motor vehicles, and will be primarily described in that context; however, it is to be understood that the bus bar system of the present invention may be used with equal advantage in power distribution systems associated with industrial equipment, home appliances, communications, equipment and the like.
The bus bar system of the present invention is based upon the use of molded, preferably, polymeric, components which are metalized, preferably by the lamination of metal foils thereonto. Metalized polymeric components have previously been employed in a number of electrical and electronic applications; however, the prior art has not recognized that metalized components can be utilized to form a power distribution bus bar system. U.S. Pat. No. 5,795,171 discloses a polymeric electrical terminal having a plated or screen-printed conductive coating thereon. U.S. Pat. No. 5,873,751, discloses a molded circuit board which includes conductive traces formed thereon, preferably through the use of a curable, electrically conductive ink. U.S. Pat. No. 5,427,532 discloses polymeric connectors which have metalized contact traces formed thereon, preferably by electroplating. U.S. Pat. No. 5,777,850 discloses the use of an electrically conductive foil in connection with a circuit board disposed in a junction box, and U.S Pat. No. 5,457,057 discloses photovoltaic modules which includes flexible photovoltaic generators having copper foil bus bars adhered thereto. None of the prior art discloses a power distribution bus system of the type described herein below, which includes an assemblage of discrete plates having conductive foil traces laminated thereto.
As will be described hereinbelow, the present invention provides a power bus system which may be assembled into a variety of configurations, utilizing standard components. The system of the present invention is readily adaptable to modular power distribution systems, and has significant utility in complex power distribution systems of the type utilized in motor vehicles, industrial equipment, electrical appliances and the like. These and other advantages of the invention will be apparent from the discussion, description and drawings which follow.
There is disclosed herein a bus bar assembly for establishing electrical communication between a power supply, an electrical device, and an electrical circuit. The assembly of the present invention includes a first and a second bus bar plate. Each plate is a generally planar member fabricated from an electrically insulating material, such as an injection molder polymer. Each plate has at least one contact tab defined on an edge thereon. The tab projects from the edge and is coplanar with the remainder of the plate. A pattern of electrically conductive material, preferably a thermally embossed metal foil is disposed on a portion of each plate so that the conductive pattern extends onto, and covers at least some of the contact tab of each plate. The first plate includes a connector for establishing electrical communication between a battery or other source of electrical power and the conductive pattern on the plates so that the power can be conveyed to the contact tab. The second plate includes means for connecting an electrical circuit to the conductive pattern on that second plate. The connector means may comprise a connector tab projecting from the second plate. A spacer allows the plates to be secured to one another in a plane parallel relationship so that the conductive patterns on the plates are in a spaced-apart relationship. The spacer, in one embodiment, includes molded-in components on the plates such as pins and sockets.
In the assembly of the present invention, the contact tab of the first plate, and the contact tab of the second plate are configured to engage respective terminals of a fuse or other such electrical device. In this manner, an electrical device which is secured to the contact tabs bridges the first and second conductive patterns and allows for the flow of electrical current from the power supply to the remainder of an electrical circuit which is connected to the conductive pattern on the second plate. In specific embodiments, the plates include a plurality of contact tabs, and they can further include a number of connector tabs which have the conductive pattern extending thereonto. The connector tabs are employed to establish electrical connection to the remainder of an electrical circuit. In specific embodiments, the connective pattern is formed from a copper metal foil. In specific embodiments, the plates are formed from an injection-molded thermoplastic material, which is a high-strength nylon or the like.
Also disclosed herein are methods for the fabrication and use of the bus bar assemblies.